1. Field of the Invention
This invention relates in general to illumination systems for tools requiring a beam of directed light to illuminate a working area or target object and, in particular, to a fiber optic cable connectable between such a tool and a light box. More specifically, but without restriction to the particular embodiment hereinafter described in accordance with the best mode of practice, this invention relates to a bifurcated single head light bundle for use with a light box having a pair of lamps capable of being illuminated consecutively to provide extended operating time for the tool.
2. Discussion of the Related Art
There has previously been proposed a number of imaging tools for probing into generally inaccessible passageways or cavities to locate a target object or a particular working area. These tools include endoscopes and laparoscopes used for diagnostic imaging purposes in the medical fields and borescopes as employed in non-medical applications such as inspecting turbine engines or other mechanical devices. These imaging devices typically include a probe having a head portion with an illumination system for illuminating the target object or working area, an imaging system, and a video monitor for viewing an image of the object or area under investigation.
In the medical field, recently developed minimally invasive surgical techniques include endoscopic and laparoscopic examining methods. Endoscopic methods generally encompass visualization of internal body structures by use of an endoscope which is inserted into an orifice or through a previously positioned trocar. Laparoscopy generally refers to visual examination of the interior of the peritoneal cavity by use of a laparoscope introduced into the cavity through the abdominal wall or the vagina. The illumination system of the endoscope or laparoscope typically includes a light box and a fiber optic cable connectable between the scope and the light box. The scope or probe itself also includes fiber optics for transmitting light from the cable to the probe head. In this manner, the scope is manipulated so that an object or area of interest can be positioned adjacent the head and directly illuminated. The imaging system of such scopes or imaging tools may include a charged coupled device (CCD) imager chip positioned in the head of the tool and associated circuitry for receiving an image of the object or area positioned near the head of the probe and transmitting that image to the video monitor. The image processing circuitry converts raw video information received from the imager chip into a monitor ready standard format signal suitable for the particular video monitor. This includes, for example, a standard NTSC, PAL, or Secam color video signal.
Surgeons performing minimally invasive medical operations commonly employ a method of triangulation in association with endoscopic or laparoscopic examining techniques. This method of triangulation involves the use of an endoscope or laparoscope as an imaging tool and at least two other surgical instruments introduced into the surgical site through a body orifice or by use of a trocar. The surgeon observes a displayed image of the target object or working area on the video monitor and performs the desired surgery in a minimally invasive manner by manipulating and operating the surgical instruments deployed in accordance with the techniques of triangulation. During this type of surgical procedure, proper functioning of the scope's illuminating system is critical. In the event the source of illumination in the light box fails, the image on the video monitor will quickly fade to black thus making the surgeon's task impossible. In this situation, the medical procedure must be interrupted and the equipment problem corrected before surgery can resume. This type of illumination source failure is typically encountered when the source lamp simply burns out at the end of its expected life.